Higher trialkylaluminum compounds (HTAC), R303Al (I), in which the alkyl groups contain more than 4 carbon atoms, are useful particularly as chemical intermediates for the synthesis of α-alcohols of the formula R32R33CHCH2OH (II) wherein R32 is hydrogen or alkyl and R33 is alkyl. α-Alcohols containing 10 to 20 carbon atoms are useful as intermediates for the synthesis of detergents and other surfactants. Therefore improved methods of making (I) and/or (II) are commercial interest.
Generally speaking, linear α-alcohols are often made utilizing the following steps, see for instance B. Elvers, et al., Ed., Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A28, 1996, p. 505-508 and references therein, and J. I. Kroschwitz, et al., Ed, Encyclopedia of Chemical Technology, 4th Ed., Vol. 1, John Wiley & Sons, New York, p. 894-903 and references therein, both of which are hereby included by reference.                (a) Triethylaluminum is produced by contacting under relatively high pressure and temperature a mixture of aluminum, hydrogen, ethylene and triethylaluminum (TEA). “New” TEA is produced in the reactor. The liquid product is removed from the reactor, filtered and some is recycled back to the TEA reactor and some is used in the next step.        (b) The TEA used in the next step is now mixed with more ethylene under high pressure and with heating. The ethylene adds sequentially (oligomerizes) to each of the original ethyl groups in the TEA, forming HTACs.        (c) The product of the previous step is mixed with oxygen (a highly exothermic reaction) to form the corresponding trialkoxyaluminum compounds.        (d) The trialkoxyaluminum compounds are hydrolyzed to form an alpha-alcohol mixture and alumina.        
This process is effective but requires the use of high temperatures and pressures in two steps, and in these two steps pyrophoric alkylaluminum compounds are present, and so these steps must be done very carefully to protect the plant and workers safety. This adds to the cost of the overall process. Processes which would minimize such steps, and/or require less capital investment, and/or have lower operating costs, would therefore be favored.
U.S. Pat. No. 3,207,770 and W. Gerhartz, et al., Ed., Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A1, VCH Verlagsgesellschaft mbH, Weinheim, 1985, p. 545-549, describe the reaction of lower trialkylaluminum compounds (LTAC) with (usually) higher olefins. The use of higher olefins made with transition metal containing ethylene oligomerization catalysts is not mentioned.
U.S. Pat. Nos. 6,103,946,4,689,437, 3,644,564 and 5,382,738, which are all hereby included by reference, describe the use of various transition metal containing catalysts to make olefins or mixtures of olefins by oligomerizing ethylene. No mention is made of making trialkylaluminum compounds or α-alcohols from those trialkylaluminum compounds.
B. Elvers, et al., Ed., Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A28, VCH Verlagsgesellschaft mbH, Weinheim, 1996, p. 505-508 and references therein, describe the overall commercial synthesis processes for making α-alcohols, including the synthesis processes for making HTACs.
U.S. Pat. Nos. 2,959,607, 3,180,881,3,389,161, 3,474,122, 3,494,948,4,918,254 and 5,278,330 describe a process for the production of higher alkylaluminum compounds from (relatively) lower alkylaluminum compounds and one or more higher olefins. The use of a transition metal containing ethylene oligomerization catalyst to form olefins is not described. U.S. Pat. Nos. 2,959,607 and 5,278,330 also describe the steps of oxidation of trialkylaluminums and the hydrolysis of the resulting trialkoxyaluminum compounds.